Multi-component Induction Logging Tool Eccentricity Correction
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Solution Overview
Problem
Conventional electromagnetic induction well logging tools are unable to accurately measure vertical conductivity and anisotropy in earth formations, as they are sensitive only to horizontal conductivity, and do not account for tool eccentricity or fractures, which can significantly affect multi-component measurements in deviated boreholes.
Innovation Solution
A method and apparatus that use multi-component logging tools to estimate the angle of azimuthal disturbances caused by tool eccentricity or fractures, rotating measurements to correct for these effects and determine resistivity properties, including horizontal and vertical resistivity, relative dip angles, sand fraction, water saturation, and permeability, using skin-effect corrected measurements and multifrequency focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic induction well logging tools use transmitter and receiver coils aligned with the longitudinal axis of the well logging device, then the measurements are simple to obtain, but the tools are sensitive only to horizontal conductivity and cannot determine vertical conductivity or anisotropy
Solution Approach 1:
The coil array is segmented into multiple transmitter coils and receiver coils with different orientations (longitudinal and transverse). This segmentation allows the tool to measure both horizontal and vertical conductivity components separately, enabling determination of formation anisotropy while maintaining a manageable device structure.
Solution Approach 2:
The invention adds a transverse dimension to the coil orientations by introducing coils perpendicular to the longitudinal axis. This dimensional expansion from single-axis to multi-axis coil configuration enables measurement of vertical conductivity in addition to horizontal conductivity, resolving the limitation of conventional single-orientation tools.
2Measurement precision
If multi-component logging tools are used in deviated boreholes, then more comprehensive resistivity data can be obtained, but tool eccentricity and fractures cause azimuthal disturbances that degrade measurement accuracy
Solution Approach 1:
The system measures the azimuthal disturbance angle caused by tool eccentricity or fractures, then uses this information to rotate the multi-component measurements into the correct coordinate system. This feedback loop compensates for the harmful azimuthal disturbances and restores measurement accuracy in deviated boreholes.
Solution Approach 2:
The invention changes the measurement parameters by rotating the measured conductivity tensor according to the estimated azimuthal disturbance angle. This parameter transformation corrects the distorted measurements and enables accurate determination of horizontal and vertical resistivity properties even in the presence of eccentricity or fractures.
3Measurement precision
If conventional induction logging techniques are used, then the instrumentation is simple, but they cannot determine formation anisotropy or vertical conductivity
Solution Approach 1:
The multi-component logging tool is designed with universal functionality to perform both conventional horizontal conductivity measurements and advanced vertical conductivity/anisotropy measurements. By integrating multiple coil orientations in a single tool, it replaces the need for separate specialized tools while providing comprehensive formation characterization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate determination of resistivity properties in deviated boreholes by correcting for tool eccentricity and fracture effects, improving the reliability of resistivity measurements and petrophysical parameter estimation.
Implementation Method 1
One or more transmitter coils are energized by an alternating current. The oscillating magnetic field produced by this arrangement results in the induction of currents in the formations which are nearly proportional to the conductivity of the formations.
Implementation Method 2
These currents, in turn, contribute to the voltage induced in one or more receiver coils.
Implementation Method 3
skin-effect corrected measurements
Data Source
AI summary
Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole.